The present invention relates to a new and distinct Penstemon and given the cultivar name of ‘Dark Towers’. Penstemon is in the family Scrophulariaceae. The new cultivar originated as part of planned breeding program at the University of Nebraska to improve Penstemon digitalis ‘Husker Red’. The seed parent was Penstemon digitalis ‘Husker Red’ (an unpatented plant) and the pollen parent was Penstemon ‘Prairie Splendor’ (Penstemon cobaea×Penstemon triflorus), an unpatented plant.